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{-# LANGUAGE MultiParamTypeClasses, UndecidableInstances, FunctionalDependencies #-}
{- |
Copyright : 2006-2007 Cale Gibbard, Russell O'Connor, Dan Doel, Remi Turk, Eric Kidd.
License : OtherLicense
Stability : experimental
Portability : non-portable (multi-parameter type classes, undecidable instances)
A type class for random number generation monads. See
<http://www.haskell.org/haskellwiki/NewMonads/MonadRandom> for the original
version of this code.
Instances of this type class include 'Control.Monad.Random.Rand' and
monads created using 'Control.Monad.Random.RandT'.
-}
module Control.Monad.Random.Class (
MonadRandom,
getRandom,
getRandomR,
getRandoms,
getRandomRs,
MonadSplit,
getSplit
) where
import System.Random
-- | An interface to random number generation monads.
class (Monad m) => MonadRandom m where
-- | Return a randomly-selected value of type @a@. See
-- 'System.Random.random' for details.
getRandom :: (Random a) => m a
-- | Return an infinite stream of random values of type @a@. See
-- 'System.Random.randoms' for details.
getRandoms :: (Random a) => m [a]
-- | Return a randomly-selected value of type @a@ in the range
-- /(lo,hi)/. See 'System.Random.randomR' for details.
getRandomR :: (Random a) => (a,a) -> m a
-- | Return an infinite stream of randomly-selected value of type @a@
-- in the range /(lo,hi)/. See 'System.Random.randomRs' for details.
getRandomRs :: (Random a) => (a,a) -> m [a]
-- | An interface to monads with splittable state (as most random number generation monads will have).
-- The intention is that the 'getSplit' action splits the state, returning one half of the result, and
-- setting the new state to the other.
class (Monad m) => MonadSplit s m | m -> s where
getSplit :: m s
|
